Magazine unit and feed structure for air stapling gun



Jan. 14, 1958 j l.. R. CAMPBELL. ET AL 2,819,466

MAGAEINEUNIT AND FEED STRUCTURE EUR AIR STAPLING GUN INVENTOILS- ffCAMPAM'AE ,Aeg/VA 361er y Azra/v Sayaf/waa Aria/@Mfrs Jan. 14, 1958 L.R. CAMPBELL ET AL MAGAZINE UNIT AND FEED STRUCTURE FOR AIR STAPLING GUNOriginal Filedl Aug. 24, 1951 4 Sheets-Sheet 2 Jan. 14, v1958 L. R.CAMPBELL ET AL 2,819,456 f MAGAZINE UNIT AND FEED STRUCTURE EUR ATRsTAPLTNG GUN 4 snegs-sheet :5

Original Filed Aug. 24, 1951 Jan. 14, 1958 1 R. CAMPBELL ET AL l2,819,466

MAGAZINE UNIT AND FEED `STRUCTURE FOR AIR STAPLING GUN original FiledAug. 24, 1951 4 sheets-sheet 4 Tm@ ammmm MAGAZINE UNIT AND FEEDSTRUCTURE FOR AIR STAPLING GUN Original application August 24, 1951,Serial No. 246,491, now llatent` No. 2,713,165, dated `.Iuly 19, 1955.Di

` vided and this application November 29, 1954, Serial 15 Claims. (Cl.1-49) rlhis invention relates to a power driven gun, and specically agun driven by air for driving staples, tacks, brads, or otherfasteningdevices through readily pierce* able material such as upholstery fabricsor the like which it is desired'to attach toafoundationbacking.

Although `thin wire staples have been used for many years for clippingpapers together as a part of ordinary office practice, it is onlycomparatively recently that the employment ofsuch staples has spread toindustrial uses.

Such staples areused in the form 4of long strips comprising a"` largenumber of individual staples interconnected together for convenience inplacing them in a stapling device. r

The stapling device,.as employed for office use, comprises a combinedstaple strip magazine and driving head pivotally mounted ona suitablebase, the staples being secured together insuchway that a strip ofstaples may beput upon a feeding track of the magazine and by strikingthe pivotally mounted driving head the staples are detached one by onefrom the strip thereof and driven secure togethenj In comparativelylrecent years, the employment of such staples hasspread toiindustrialuses. As heretofore used industrially, the staple driving device hasbeen hand driven and patternedessentially along the lines of the head ofthe oiiice stapling machine removed from the customary base so that it`can be` used for driving staples or other fastening devices in `anydesired location. Industrial use of such devices however-,.has'notproven satisfactory for use in mass productionlbecause of the fatiguefactor.

The principal object of the present invention is to provide an airstapling gun, namely, one in which the staple driver which causes thestaple to be driven through the work tofbe stapled is actuated by apiston driven by air under pressure.`

We have found after a long period of experimental development workn inorder that a stapling air gun work satisfactorily, itis absolutelyessential that the air piston which drives the driver, by means of whichthe staple is propelled throughfthe materials to be fastened together,shallwork 'with a sharp, quick driving actioniand` not a merepushingaction such as characterized many, of the prior art.devices, v t

L Afurther `important part in the development ofa practical air-drivenstapling gun for industrial use centers about the `constructionaldetails and developmenttofm) the valve by means of which air is`admitted to the` air cylinder and piston so as to insure a quick,sharp, positive driving .action,` as distinguished froml a' slowerlpushing action, ofthe driving element by.l means ofnwhich4 the stapleisdetached from the staple strip andV driven through thev material to befastened together;.(b)"anexpansion chamber` in `the air conduit leadingtothe valve to act as an accumulator and thus insure an adequate supplyof air nited States Patent() er'V ICC

towhich they` are subjected by the workers, while being of minimumweight for easy handling.

As it is necessary from time to time to use dierent Siae staples orother fastening devices, .it is highly desirable that the guns be somade as to be readily convertible for use from one size staples toanother.

One of the principal objects of the present invention is to, provide anewand improved construction of a power unitV for an air stapling gunwhich includes the necessary air conduits, an accumulator chamber, theair piston and cylinder, the valve by means yof which air is admitted tothe cylinder, all in a unitary assembly, to and from which any one of aplurality of staple strip magazine units, de-

signed for use with different size staples or other fastening. devices,may be readily and quickly attached or detached.

A further object is to provide a new and improved construction andarrangement of the spring means for actuatinglthe` staple strip pusherwhereby the pusher spring is located out of the line of travel of thestrip pusher thereby enabling a longer stripof staples to be used andwhereby4 the same spring means also serves to hold the i pusher snuglyin contact with the staple track and in 4 .through the papers orothermaterials` that it is desiredito engagement with the rear end ofthe strip of staples.

Another object is to providea new and improved constructionof a staplemagazine and staple feed structure including a track cover whichcooperates with a stapte strip pusher and the actuating springstherefor, said cover being slidable to an open position to expose thestaple track for the insertion of a new strip of staples andso thatthestrip pushersprings will `be properly tensioned by theclosing of saidcover.

A still further object is to provide a new and improved construction ofa unitary assembly for a plurality of magazine sections, each of whichincludes a track designed for the accommodation of one of the manydiiferent sized staples or other fastening devices that are to beemployed,

'u the magazine units alsoincluding as a unitary part thereof a driverfor detaching the staples individually from a strip thereof and a nosepiece through which the staples are vdriven into the materials to befastened..

Anotherfobject is to provide a new and improved conr struction of apusher device whereby the strip of staples will be positively andaccurately fed to the driver and in.

i will appear more fully from thefollowing more detailed description andby reference to the accompanying drawings forming a part hereof,wherein: .i

Fig. l is a longitudinal Verticalview partly in section of an air-drivengun for driving staples constructed in` accordance with the principlesof the present invention;

Fig. 2 is a section taken substantially` ontthe line 2 2 of Fig. l of atrack section of a stapletmagazine unit for narrow crown staples; i

Fig. 3 is a section similar to Figi, `a magazine` track section for widecrown staples;

Fig. 4 is an exploded view of parts of the unit shown in Fig. 3;

Fig. 5 is a horizontal sectional detail taken on the line 5-5 of Fig. 1through the cap or closure for the air cylinder;

Fig. 6 is a horizontal section on the line 6-6 of Fig. l;

Fig. 7 is an exploded view of the parts which are combined to make upthe magazine and staple driver unit for narrow crown staples;

Fig. 8 is a section on the line 8-8 of Fig. 1 through thenarrow-crown-staple magazine and track unit;

Fig. 9 is an inverted perspective View of the magazine track cover andpusher employed with the narrow crown staples;

Fig. 10 is an exploded View similar to Fig. 9 showing the parts of amagazine unit employed for wide crown staples;

Fig. 11 is a section taken on the line lll-l1 of Fig. 3 through thewide-crown-staple magazine unit;

Fig. 12 is an enlarged detail perspective view showing the jamb plateend of a track section for a wide crown staple;

Fig. 13 is a longitudinal sectional detail through a wide crown magazineunit showing the manner in which the staple pusher serves as a stop tolimit the opening movement of the track cover;

Fig. 14 is a perspective view showing the staple pusher for the widecrown staples and the means for fastening the end of the pusher springthereto;

Fig. 15 is a view showing a retaining clip employed for holding theconstituent parts of a magazine and driver unit in assembled condition;

Fig. 16 is a sectional detail through a sheave for the pusher springs onthe line 16-16 of Fig. 4 for the Wide crown staples;

Fig. 17 is a section on the line 17-17 of Fig. 16;

Fig. 18 is a sectional detail showing the construction of a pusherspring retaining tab;

Fig. 19 is a section on the line 19-19 of Fig. 1;

Fig. 20 is a section on the line Ztl- 20 of Fig. 10; and

Fig. 21 is a front view of the lower portion of the nose piece shown inFig. 15 as seen from the right.

The air gun of the present invention, briefly, consists essentially ofan assembly of two parts-a combined power and handle unit and a staplemagazine unit. The handle unit includes an air cylinder and piston, thehandle being cored to provide an air expansion chamber and a single airconduit which serves as an inlet and exhaust passage for air to pass toand from the air cylinder and piston under the control of a triggeractuated valve, carried by the handle unit and interposed between theeX- pansion chamber and said conduit. The invention also includes theprovision of a plurality of magazine units, each of which is a completeunit assembly separate from the handle unit and which magazine units areconstructed in different sizes in accordance with the size of the stapleor other fastening device to be driven, each magazine unit being soconstructed and arranged that it includes a staple driver and nose pieceassembled with the magazine for the respective size staple to be used,the various magazine units being interchangeable with, and quickly andreadily attachable to and detachable from, the handle unit.

As shown in Fig. 1 of the drawings, the handle unit consists of a coredhandle 20 having at one end thereof a screw-threaded inlet opening 21having pipe threads adapted to receive a threaded bushing 22 to receivea hose nipple 23 to which is attached a hose 24 leading to a source ofair under pressure.

At its lower end the cylinder 42 is provided with in terior screwthreads 46 to receive the upper reduced threaded end 47 of an adapter4S, having a cup portion 43e (Fig. l0), the purpose of which will behereinafter more fully described.

A piston 5d is slidably mounted within the bore 5l of the cylinder 42and is normally held in its uppermost position by a coiled compressionspring 53. The top 50a of the piston is flat so as to make a closesealing tit with the inner flat face of the closure cap it? as shown inFig. 1 of the drawings. Located immediately below and in contactingengagement with the piston 59 is a cup-shaped bumper retainer having aperipheral shoulder or flange 56 at its upper end. The flange 56 servesas an abutment seat for the top coil of the compression spring 53 whilethe outer surface of the cupshaped portion of the retainer 55 serves asa locating means for the top coils of said spring, the bottom coils ofwhich are centered by their engagement within the cup portion 48e of theadapter 43. Mounted within the interior of the bumper retainer 55 is abumper 57 of rubber or other suitable resilient or yielding material.The top wall of the bumper retainer 55 is provided with an aperture 58shaped to conform to the coniiguration of a driver 60.

As shown in Fig. l, the top face of the bumper retainer 55 is at andseats against the inner llat face of the piston Sti and the aperture 5din the top portion of the retainer S5 is countersunk as indicated at 58aso that the enlarged head 60a of a driver 60 will be iiush within thehead portion of the bumper retainer 5S, all as shown in Fig. l. Theshank portion of the driver (it) is of approximately T-shapedconfiguration, as shown best in Fig. 5 of the drawing, having a pair oflongitudinally extending ribs db one on each side thereof. These ribs601: are shaped to iit neatly but slidably within a track 6l formedwithin a nosepiece 62 as shown best in Fig. 6.

As many diierent size staples are used industrially, for example, tosecure upholstery or other fabrics to foundation pieces in theautomotive industry, the gun of the present invention consists of twoseparate units, a power unit, which comprises the handle 2? with the aircylinder 42, piston Sil and air valve asesrnbly 27, 2S forming one unitand a staple magazine forming another unit.

Each magazine unit consists of a track section, together with a trackcover and nosepiece 62 which is designed for the particular size ofstaples for which the gun is to be used at any particular time; thedriver 60, together with the nosepiece 62 being proportioned and shapedin accordance with the size of staples to be driven.

In the exploded view of Fig. 7 of the drawing we have shown a nosepiece67;, together with the track section and other parts that go to make upa magazine unit for the driving of narrow-crown staples. Thesenarrow-crown staples for which the parts shown in Figs. 6, 7 and 9 areadapted to be used are approximately 3/16 of an inch between the stapleprongs.

In accordance with the present invention we provide a plurality ofstaple magazine unit assemblies which may be quickly and readilydetached and attached from the handle section. The parts which go tomake up a staple magazine unit per se comprise a screwthreaded adapteri8 and a nosepiece 62, together with a staple supporting track and atrack cover which carries a staple pusher and the springs to actuate thepusher presently to be dcscrioed. A magazine -assembly also includes adriver 60, a bumper retainer 55, a resilient shock absorber 57 and apiston return spring 53 as hereinafter described.

As shown in Fig. 6 of theV drawing, the nosepiece 62 is provided with aguideway 64 into which fits the portion 63 of the driver 6b. Thenosepiece 62 is also provided with a track section 6l into which iit thelongitudinal ribs 60h of the driver 6i?. At its upper end the nosepieceis reduced, as indicated at 65 (Fig. 7) to receive a sleeve that servesas a stop against which the bumper 57 strikes when the piston reachesthe end of its driving stroke, sleeve 1.20 being seated on a shoulder12661 formed by enlarged part 66 of nosepiece 62. lt will, of course.

be understood that the trackway 61` formed in the nosepiece is soproportioned as.=to receive but one staple at a time which tits snuglybut slidably therein to prevent spreading of the staple legs las thestaple is driven into the material and that the trackway extends theentire length of the nosepiece 62; and is open at both the top andbottom ends of the nosepiece. It will be likewise understood that thelower end` of the nosepiece may be extended as far beyond the lower faceof the track section as `may be desired for reaching into otherwiseinaccessible places.

The adapter 4S by means of which the magazine unit is attached to thehandle unit, as shown in Figs. 7 and 10 of the drawings, in addition tohaving the upper reduced screw-threaded portion 47, has a pair ofdepending legs 48a which are adapted to `embrace the widened portion 67of `the nosepiece and are suitably brazed thereto after the parts havebeen assembled( The magazine section, as shown best in Figs. 7 and 8 ofthe drawings, consists of a lower track section 75 having a pair ofbeads 76 on each side thereof that form longitudinal grooves which serveas a track for the lower anges 80 extending laterallyfrom the loweredges of the side walls of a track cover member 77 made of a sheet steelstamping bent into a general U-shaped conguration. Secured, preferablyby spot welding to the inner face of the bottom web of track section 75is a track proper 78 which is of the proper size to tit between the legsof the staples to be driven; in this case, the narrow-crown staples.

Mounted on and brazed to the front end of the track section 75 is a jambplate 79 which when the parts are assembled is adapted to abut tightlyagainst the flat face of the widened section 67 of the nosepiece.

The ears 71 at the front end of track section 75 are adapted to,straddle the side faces of the widened section 67 of the nosepiece. Inassembling the magazine unit the track section 75 with `the ears 71astraddle section 67 has the jamb plate 79 abutted against the flatinner face of the widened section 67 of the nosepiece 62 and with thebottom of the `jamb plate 79 resting upon the ledge 63 of the nosepiece.The legs 48a of the adapter 48 are then slipped down and astraddle theears 71 and with the turned portion 66 of the nosepiece fitting neatlywithin the central hole 423C of the adapter.

.For convenience in manufacturing, the underface of the widened flangeportion 4811 ofthe adapter has a couple of small holes drilled in itbetween the legs 48a and the hole 48e in which are placed small slugs ofcopper brazing material. The nose piece and track section, together withthe adapter, are placed in assembled condition in a fixture so as tohold the nosepiece at an exact right angle to the track section and,with the parts so assembled in the fixture, a light projection weld ismade through the assembly at 43C (Fig. 7). Brazing material is thenplaced around the edges of the parts which are in contact and the unitis then placed upright in a heating furnace and since the holes in whichthe brazing slugs `are placed are open at the bottom, when the slugsmelt the brazing material .thereof together withv that placed around theedges will seep by capillary action between Vthe entire contactingareasof the assembled parts to form a fused joint therebetween whichunites the parts together in assembled condition as a substantiallyintegral strong rigid unit. f

As shown best in the inverted view Fig. 9 the track cover 77 contains apusher S1 for pushing the clips ot staples forward to the driving end ofthe machine. The pusher 81 is of U-shaped configuration so as to titslidably over the top of the track member 78 shown in Fig.` 7. 'At theiri lower rearward ends the side walls of the pusher are provided with apair of tabs 82 to which are adapted to be secured the forward terminalcoils of a pair of coiled pusher springs 83. Each of these coil springsis trained about a pulley84 rotatably secured by means of rivets, orother securing devices, to the side wall of the cover section. Therearward ends of the springs 83 are anchored tothe inwardly .projectingtabs 85 struck out from the side `f6 wallsof the track cover 77.`bending down the top wall of the track cover is provided to facilitatemoving the cover 77 to open position while the rear face of the widesection of the nosepiece 62 forms '1. a stop with which the forwardextension 115 of the top Wall of the track cover engages to limit theforward travel i of the cover section in its closed position and preventit from extending into the trackway 61 of the nosepiece 62.

ing 170 the jamb plate 79 is provided with inclined camA faces 79e (Fig.7) for directing the prongs of the staples into the trackway 61.

For the purpose of permittinglthe staples to enter laterally into thetrack section, thelatter is relieved, or cut away, as indicated at 69 byan amount just sufficient to permitthe staples to enter trackway 6lwhile leaving the side walls of the trackway 61 of the correct dimensionto hold the staples against spreading-as they are driven4 into thematerial with which they are to be used.

` ltwill be noted that the attachment of the ends of the lower runs ofthe springs 83 to the tabs 82 formed on the` `lower rear end of thepusher 81 causes the springs to `,snugly against the lower track section75 to insure a exert a` downward pull on the back end of the pusher soas to cause the lower edge thereof to be held snugly iii Contact withthe top face of the track 78 and thus hold the pusher in an inclinedposition as shown best in Figs. l and 13. the pusher 81 to engage thebottom of the legs of the staples tobefed and thus insure that thebottom legs ot the staples willbe fed into the track 61 of thenosepiece. This together with the cam faces '79e will tend to preventthe legsot a staple as it is severed from thel strip from being turnedbackwardly into the track section of the magazine unit, thus causingjamming of the staple feeding mechanism.

At its rearmost end the track section 78 is provided with adownwardlyinclined section which terminates at l the rear `end of thetrack in a lug or shoulder 88 with which the rear end of the pusher 81contacts to serve to limit the opening movement of the track cover 77when p it is pulled backwardly to insert a new strip of staples.

In the case of the narrow crown staples, the tabs S2` to which the frontends of the springs 83 are secured project laterally outward suicientlyto engage with the rims of pulleys 84 so that when the track cover ismoved rearwardly to open position it will pick up the pusher and piillit to the rear end of the track. As the points of Contact of these tabswith the pulley rims serve as fulcrum points about which the downwardpull of the lower run oi the springs 83 is exerted, the rear end of thepusher will beheld snugly against the top face of track 78 and thusinsure the engagement of the rear end of vthe pusher with the stops 88(Fig. 3) at the top rear end L of the track '7d thereby to limit theopening movement of the track cover 77.

Secured to the top of the track cover 77 is a at leaf spring 89 which isprovided intermediate its ends with a` hump portion 9d and terminates ina linger tab 91 by means of which the spring may be depressed. The hump90 is adapted to engage behind a filling piece 92 brazed or otherwisesecured to Vthe inner face of the web of a yoke 93, the lower legs.ofwhich are attached to the side walls of the track section 7S, and thuslock the track cover in its closed position; the spring 819 togetherwith i aninclined surface 48d (Fig. l) on the under side of the flange48h of the adapter 48 holding .the cover down A linger grip 86 formed byThis causes the lower end of the front face of.

proper predetermined clearance between the top of the track 78 and theunder surface of the top wall of the track cover and thus permit freesliding movement of the staples and pusher 81 along track 78. Thefilling piece 92. also serves as a means for providing the necessaryscrew threads to receive a fastening screw 9d by means of which the rearend 2da of handle unit Ztl is secured to the staple magazine unit toprevent the handle from rotating or swinging sideways out of line withthe magazine unit when the device is in use.

In Figs. 3, 10 and 12, we have shown the parts of a magazine unit forwide-crown staples. As shown in Fig. l0, the parts which comprise themagazine for widecrown staples are essentially the same as shown inFigs. 7 to 9 for the narrow-crown staples, except there ,are differencesin details of construction ldue to the difference in width of thestaples to be fed. As shown in Fig. l the nosepiece 62a is provided witha trackway 51a similar to the trackway 6lof the nosepiece 62, exceptthat it is, of course, wider for the wider crown staples. At its top endthe nosepiece 62a is provided with a reduced portion 65a which is of a.diameter such that the ilange of the cup-shaped end of the bumperretainer 55 will pass over it when the latter is driven downwardly toexecute a driving stroke, the top face of the nosepiece serving as anabutment against which the lower face of the yielding bumper 57 strikes.immediately below the reduced end 65a of the nosepiece it is providedwith a portion of larger diameter 66a adapted to iit Within hole the ofthe adapter 48, and, just below the portion 65a, the nosepiece 62a isprovided with a widened portion 67a similar to the portion d'7. Theinner face of the widened portion 67a of the nosepiece 62a is also cut.away as at 69a to provide a ready entrance for the staples laterallyinto the trackway 61a of the nosepiece.

Secured to the track section 75a for the wide-crown staples (Fig. is atrack member proper in the form of a channel shaped piece 78a, the lowerwall or web of which is spot welded to the track section 75a. At itsfront end the channeled track '7&1 proper is closed by a jamb plate 79asuitably brazed to the legs of the channeled track 78a. The jamb plate79a is provided with a pair of laterally projecting curved cam faces 79d(Fig. l2) similar to the cam faces 79C which serve to engage the lowerprongs of .a staple and direct them positively into the trackway 61a ofthe nosepiece 62a as the staples are engaged by the driver to separatethein from the strip of staples and force them downwardly into thematerial to be fastened.

The front end of the track section 75:1 is provided with a pair of ears71a similar to the ears 7l shown in Fig. 7 which .are also adapted tostraddle the widened section 67a when the parts are assembled.

Due to the fact that the space between the prongs ot' the wider crownstaples provide ample room for the housing of the spring 83a used forforcing the staple pusher 81a against a strip of staples, in the formfor. the wide-crown staples shown in Figs. 4 and l@ to 13 only a singlespring 83a is used. This spring 33a has its rearmost end secured to atab 85a struck from `a spring housing member 9b shown best in Fig. 4,while the spring intermediate its ends is coiled about a single sheaveor pulley 84a. The forward end of the spring is fastened to a tab 82aformed or struck out from the rear end of. a horizontal weh thatconnects the side walls of a U-shaped piece 130 welded to the inner faceof the top wall of the U-shaped pusher member 31a as shown in Fig. 14.

After the spring 83a is assembled in the spring housing 9) as justdescribed the hooked end 9i of the housing 90 is hooked through the slot92 in the rear end of the track cover 77a (Fig. 4); the engagement ofthe rear face of the hooked end 91 with the rear end of the track cover77o preventing movement of the spring housing 9i) longitudinally of thecover. 'the ends tlc of the shaft portion of the sheaves 64a engageangular portions b at the front of the walls 126 when the track cover ismoved rearwardly thus carrying the pusher withv it. The shaft ends 11dealso serve as abutment stops against which the angular surfaces lltb(Fig. i4) of the pusher Sla abut when the track cover is pulled back toits fulll opened position and :as fulcrum points against which the pullof the lower run of spring 33a is exerted to hold the rear end of thepusher snugly against the top face of track 73a and thus insureengagement of the rear end of the pusher with the stops 88a (Fig. 3)thereby to limit the opening movement of the track cover 77a.

As shown in Fig. 17, the pitch line of the sheaves 84, 84a for thesprings 83, 83a is so arranged that the coils of the springs at theirlowermost end will be forced into close contacting engagement withadjacent coils and thus prevent the formation of a space `at the pointwhere the coils contact with the sheave that would permit' them tobecome engaged or hooked over the sheave in such way as would preventthe free travel of the spring over the sheave.

As shown in Fig. 18 the construction and arrangement of the tab 82a onthe pusher element 81a is such thatl there is sufficient space betweenthe ends of the tab and the body of the material from which it is struckout to permit the two terminal coils with which the spring 83a is provided to slip readily under the tab when the spring is held at a. rig; tangle to the pusher but which space is insuff cient to permit the twocoils to pass through it and thus become accidentally detached from thetab when the body of the spring lies in its horizontal operativeposition as shown in Fig. 4.

The track section for the Wide-crown staples is asseinbled to thenosepiece 62a and adapter 4S in a fixture and then the parts are brazedtogether as hereinbefore described.

After the track section for either the wide-crown or narrow-crownstaples has been properly assembled to the nosepiece, either 62 or 62awhich goes with the particular track section, in the fixture providedfor such purpose, and the parts have been integrally united together asa unit by spot Welding and brazing as hereinbefore described, the trackcover for the particular size staple is then placed over the tracksection proper, with the pusher $1 or 81a, as the case may be, held inplace by the fingers of the person doing the assembly work, the pusheris engaged over the respective track 78 or 7&1, and the cover is slidhome until the end of the cover 77a for the narrow-crown staples abutsagainst the nosepiece or an abutment piece lll brazed to the top wall ofthe cover 77 for the wide-crown staples abuts against flange 48d of theadapter 43 (Fig. l5). When this occurs, the hump 90 of the spring 8:9engages behind the iilling piece 92, as shown in Fig. 1 of the drawingsand the inclined rear face of the spring hump will force the coverforwardly and hold it in snugly locked position.

ln order to facilitate the loading of a new strip of staples in thestaple track 78 or 73a, a major portion of the side walls yof both thenarrow-crown track section 75 and the wide-crown track section 75a iscut away above the beads 76 and 76a from points adjacent to their frontand rear ends thereby to expose the tracks 78 or 78a when their trackcovers are slid to fully opened position. It will be noted that in thecase of both the narrow-crown and the wide-crown staples that after thetrack cover 77 or 77a with the respective pusher di or 85h together withthe pusher springs 83 or springs 83a respectively assembled therewithhas been placed on the track section the cover may be moved to opened orclosed position without dis` turbing the unitary assembly ot the tracksection to the .uosepiece and adapter. When a strip of staples has beenplaced on the staple track 78 or 78a the front end of the pusher engagesthe rear end of the strip and as the cover is pushed forwardly to itsclosed position the pusher will be held by its engagement with the. rearend of the `strip to- 2,819,4es y pulleys S4 or 84a will contact thepusher 81 or 81a and pull it rearwardly and as hereinbefore describedwhile the rear end of the pusher will be held snugly but yieldinglybythe pair of springs 83 or 83a, as the case may be, against thetop faceof the track 78 or 78a, to insure its engagement with the stops 83 atthe rear cud of the track and thereby limit the opening movement of thetrack Cover. If it is desired to remove the track cover 77 or 77aentirely, this may be readily accomplished by inserting a small screwdriver or the like and lifting the rear` end of the pusher against theaction of the springs 83 or springs `83a so as to permit it to clear thestop 88 or 88a.

Themannertin which a staple magazine unit is assembled isas follows: Adriver 60 of the correct size and shape to go with the staples of thesize for which the magazine unit is to be used is inserted into thebumper retainer with which it is intended to be used, the driver bumper57 rst having been inserted into the cup-shaped end of the retainer 55.A collar 12) is then placed over the end 65 of the nosepiece and pistonreturn spring 53 ,then has its lower end inserted into the cup-shapedend `of the adapter 48 and with the lower coils thereof encircling thecollar 120 on the top of the nosepiece. The driver assembly consistingof the bumper retainer 55 and driver bumper 57 is then assembled to themagazine unit by inserting the lower end of the driver 60 into thetrackway of the nosepiece 62 or 62a. After this has been done the spring53 is compressed by pressing downwardly upon the top of the retainer 55until a notch 100 in the lower end of the driver 60 reaches a positionbelow the lower face of the adapter 48 substantially as shown in Fig. 15of the drawing. The hooked end 101 of a spring clip 102 is then engagedwithin the notch 100 of the driver and the lower upturned endl103 of thespring clip is placed within a longitudinal slot 104 formed centrally inthe lower part of the driver 60. The upward thrust exerted by the pistonreturn spring `53 forces the driver upwardly and thus holds the top end101 of the spring clip 102 rmly up into the hole 48C fof the adapter 48so that the top 101 of the clip is pressed against the right-hand wall(Fig. 15) of said hole 48C thus causing the hooked end 101 to be heldfirmly within the notch 100 of the driver, while the engagement of theupturned end 103 of the clip 102 with the slot 104 prevents the springclip 102 from moving sideways and becoming accidentally disengaged.

The magazineunit assembly, consisting of the track section and `itscover, the driver 60, piston spring 53 and driver 60, bumper retainer,shock absorber 57, adapter 48 and nose'piece 61, may then be engagedwith a handle Ior power unit 20 by screwing the threads on the reducedend 47 ofthe adapter into the threads 46 formed inthe lower end ofthecylinder 42, and the magazine unit is screwedthome until the upper faceof the llange 48d of the adapter is rmly seated against the lower faceof the cylinder 42.

The cylinder closure cap 40 which is the-n backed olf a` turn or sopermit the rear end of the magazine unit to be rotated into alignmentwith the rear end 20a of the handle of the power unit, and the screw 94is then screwed into position to hold the end 20a of the handle fromrotating and with the handle secured in proper vertical alignment withthe magazine unit, the cylinder cap 40 is then tightened firmly inposition.

We have found after a long period of experimental development that thesealing contact provided between the .flat upper face 50a of the piston50 and the lower atinner surface of the cylinder closure cap is of theutmost irncylinder 42.

v As will be seen from Fig. 1 of the drawings, the drivel 60 and piston50 have an appreciable amount of travel before the lower end of thedriver engages a staple to disengage it from the staple clip and forceit: into the material to be stapled.

We have also found it to be imperative if excessive breakage of thedriver 60 is to be avoided that some shock absorbing or snubbing meansbe provided to re-Y lieve the drivers from the sharp impact or blowwhich occurs when the lower face of the skirt of the piston engages withthe relatively hard bumper sleeve 70. For this purpose we have providedthe rubber bumpermember 57 which is so proportioned and arranged withinthe retainer that the lower end of the bumper will engage the top of thenosepiece 62 at the bottom of the pistons stroke and thus cushion thehead 58 of the driver60 from the sharp impact of the blow of the pistonagainst the bumper 70.

`When it is desired to change the gun for use with a dif` ferent sizestaple the magazine unit assembly which has been employed is detachedfrom the power unit as follows: The driver 60 is driven to the extremelower end ofv its travel and by holding the valve 27 open driver` 60v isheld there. A locking clip 102 has its upper end 101 engaged within thenotch of the driver and in engagement with the adapter and with theupturned lower end 103 of the clip in slot 104 in nosepiece 6tll. Thetrigger 35 is then released and piston spring 53 will draw the driver 60snugly up into locked position.

the handle to unscrew the threaded portion 47 of the adapter from thescrew threads 46 in the bottom of the A new magazine unit assembly isthen screwed into the cylinder until the flange 43b of its adapter 43 isseatedrmly against the lower face of the cylinder. The cylinder cap 40is then backed off to permit the handle and magazine units to beproperly aligned, the screw 94 is then inserted and the cylinder cap 40rmly tightened.`

The manner in which the device operates is as follows: The handle beingattached to a source of compressed air by means of hose 24, air underpressure from said source enters through the bushing :2l into the airexpansion or accumulator chamber 25 from whence it flows into the valvechamber 26 to be immediately available for use when the valve 27 isopened.

When theoperator wishes to drive a staple, he raises the trigger 35 soas to cause it to engage with the rounded lower `end 27h of valve stem27a and thus raise and open valve 27, to admit air under pressure to thetop of cyl` between the top flat face of the piston S0 and the ilatvinner face of the cap 4t) and thus starts the piston to traveldownwardly in a driving stroke.

Upon the tirst stroke of the gun to drive a staple, the notch 100 of thedriver passes downwardly so as to release the hooked end 101 of the clip102 from its engagement with thetnotch 100 in the driver 60| and hole48e of the adapter and the clip 102 then falls` from the gun thuspermitting the piston, driver and driver head to be pushed upwardly bythe piston return spring 53 until the hat face 50a of the piston engageswith the inner tlat surface of the cylinder closure cap 40. It will beunderstood that the clip 102 is used only for i the purpose of holdingthe driver 60 and the piston return spring l5d; together with the bumperretainer 55 t andbumper 57 in assembled condition. As heretofore Thescrew 94v at the rear end of the handle 20 is then removed, cylinder 1,1pointed out, due to the fact that the invention contemplates the use ofdifferent sized magazine unit assemblies for use with the size staplesfor which the gun is to be employed and as each magazine unit whenassembled consists of the track section permanently secured as bybrazing to an adapter 48, the nosepiece 62;, a driver titl with .pistonreturn spring 53, bumper retainer S and bumper 57 and as these parts areheld in assembled condition by the clip 162 as just described, theassembled magazine unit may be kept in a storeroom or any suitable placeuntil needed for use.

It will, of course, be understood that the driver dil moves downwardlyan amount sufficient to drive the staple which has been detached fromthe strip thereof through the material to be fastened.

After a staple has been severed from the strip and driven home, theoperator releases trigger 35 thus permitting valve 27 to drop by the airpressure being exerted upon the top face of valve seat retainer 27e thusshutting oil the air flow to piston 59 and permitting the piston returnspring 53 to force the piston 5d upwardly. During the upward travel ofthe piston the air which has accumulated above the top of the piston isnow forced outwardly through the longitudinal passages 3* of thecylinder closure cap 4t), the annular passage 38 and into the conduit37, iowing from said conduit and thence through the port 2312 into thechamber 28d of the valve bushing 2-8 and around the annular meteringpassage provided between the bore of valve bushing 23 and the stem 27]'of the valve 27 and out to atmosphere through the exhaust port Asheretofore pointed out, the stem portion 27j of the valve 27 is slightlysmaller in diameter than the bore 2S of the valve bushing to provide anannular metering passageway through which the exhaust passes to theexhaust port 23C. This serves to cushion the return stroke of the pistonand avoid any hammering action by the piston on the inner surface or thecylinder closure cap 40 which would otherwise tend to he quitedestructive.

As the staples are detached one by one oy the driver 60 from the stripof staples in the magazine unit, the staple pusher 8l. under the tensionof springs 33 will feed the strip of staples so that tre foremost stapleof the strip will pass laterally into the opening di) relieved in thenosepiece 62 until the staple lies within the trackwny 6l., in positionto be engaged by the driver du on its next downward stroke.

As each staple is severed from the strip thereof the lower ends orprongs of the staple legs will er age with the cam faces '79e or 79d onthe jamb plate to the staple legs will be forced outwardly andpositively into the track 6l of the nosepiece, thus preventing the legsor prongs of the staples from turning backwardly into the track sectionof the unit and cause jamming of the latter.

For the purpose of preventing a staple pusher from being fed into thepath of the driver 6@ after the last staple of a strip has been fed andthe strip is exhausted, the forward ends of a pusher are provided with apair of small outwardly extending ears or tabs (Fig. 8) which the innerface of the nosepiece and prevent the pusher from being pushed outwardlyby the pusher springs into the trackway and in the path of thedescending driver. ln the wide-crown pusher (Fig. 14) the surfaces l10nare provided to supplement the tabs llt) and having as a humpingsurface, the back surface of jamb plate '79a (Fig. l2).

When the last staple of a strip has been driven, the operator may graspthe projecting linger piece 91 yof the spring 89 and depress it untilthe hump 9d of the spring is flexed below the filler piece 92. Theoperator may then pull the track cover section 77 rearwardly until thepusher 8l. engages the stops 3d provided at the rear end of the track 78and until the parts are in the position shown in Fig. 13; the engagementof the pusher 8l with sure that l said stops limiting the outwardmovement of the track cover. In this extreme outward open position ofthe cover 77 or 77a the cover will be supported only at its innermostend by the engagement of the pusher 81 or dla with the stops 88 or 83a;hence, the weight of the outwardly extending, overhanging major portionof the cover will tend to hold the cover in its fully opened position. Anew strip of staples may then be inserted, after which the track cover77 is shoved forwardly until the abutment lll in the case of thewide-crown staples engages the flange 48h of the adapter 43; the forwardstop for the narrow crown is the foremost end of track cover7'7-stopping against the nosepiece 62 (Fig. l).

The track covers are provided with an `observation opening lid adjacentthe adapter 4S so that the operator may readily inspect for the presenceor lack of staples on the staple track or to see if the nosepiece 62 isopen in the front and clear any staples which may have become jammed inthe track section.

It will be noted that there is but a single driving member, namely, thedriver 6), interposed between the piston and the staples and that thedriving force is imparted to the driver through the engagement of theenlarged head 60a of the driver with the flat underface of the top wallof the piston.

It will also be noted that with each form of magazine unit shown, theears 7l or 71a at the front of the side walls of the track sections 75,75a, respectively, are clamped between the solid metal of the wide part67 or 67u of a nosepiece d?. or 62a and the relatively thick legs titulaof the adapter so that an interlocked engagement of the parts iseffected whereby the parts mutually cooperate to brace each `other andform a strong rigid unit when brazed together as hereinbefore described.

While we have described and illustrated a satisfactory constructiona'lexample of our invention for use with staples that has proven highlysatisfactory in actual commercial use, it will, of course, be understoodthat the invention may be employed for driving tacks, brads, rivets orother fastening devices by modifying the magazine units, drivers andnose pieces accordingly and many other changes, variations andmodifications within the skill of the art may be resorted to withoutdeparting from the spirit of the invention as set forth in the claimshereunto appended in which the term staple is to be construed to includetacks, brads, hollow rivets or other fastening devices capable of beingmade in interconnected form for use with an air gun constructed inaccordance with the principles of the present invention.

We claim:

l. Inv a stapling machine, a staple magazine and feed structurecomprising an elongated track section having a bottom wall and a pair oflaterally spaced side walls, each of said walls being provided along itsbottom edge with an inwardly open longitudinal groove, a staple-carryingtrack secured to said bottom wall along the longitudinal central portionthereof, and a track cover of inverted U-shaped cross-section having alateral ange extending from the bottom of each side wall thereof forslidable engagement within the open longitudinal grooves of the sidewalls of said track section, thereby to hold the top wall of said coverin predetermined spaced relationship to the top of said staple-carryingtrack as said cover is slid to and from opened to closed positions.

2. In a stapling machine, a staple magazine and feed struct-urecomprising an elongated track section having a bottom wall and a pair oflaterally spaced side walls, each of said walls being provided along itsbottom edge with an inwardly open longitudinal groove, a staplecarryingtrack secured to said bottom wall along the longitudinal central portionthereof, and a track cover of inverted U-shape cross-section having alateral flange extending from the bottom of each side wall thereof forslidable engagement within the open longitudinal grooves of the sidewalls of said track section, thereby to hold the top wall of said coverin predetermined spaced relationship to the top of said staple-carryingtrack as said cover is slid to and from opened and closed positions, andthe upper major portion of the side walls of said track section beingcut away from points adjacent to the front and rear ends thereof toexpose said staple-carrying track for easy accessibility thereto and tofacilitate the loading of staples thereon when said cover is moved toopened position.

3. In a stapling machine, a staple magazine and feed structurecomprising a track upon which a staple strip may be slidably supported,a track cover slidably mounted over said track, and a staple-stripfeeding assembly comprising a staple pusher for slidable engagement withsaid track, a housing detachably connected at its rear end with the rearend of said track cover and having a sheave pulley rotatably mounted atthe front end thereof, and a coiled tension spring encased within saidhousing having its front end connected to said pusher, its rear endconnected to said housing and its intermediate portion trained aboutsaid sheave pulley.

4. In a staple machine having a staple driver, a staple magazine andfeed structure comprising a track section having a track upon which astrip of interconnected staples is slidably supported to be fed t-o saiddriver, a track cover slidably carried by said track section formovement to and from a closed to an open position to expose said trackand permit it to be loaded with a staple strip, staple strip feedingmeans comprising a staple pusher slidably mounted on said track and acoiled tension pusher spring attached thereto supported by said coverfor movement therewith for causing said pusher to engage said staplesand feed them one at a time to said driver, and stop means on said trackfor engagement by said pusher for limiting the opening movement of saidcover, said pusher spring normally urging said pusher in a position toengage said stop means when said cover is moved to its fully openedposition.

5. A staple magazine unit and feed structure as set forth in claim 4 inwhich a rotatable sheave pulley, about which said spring is trainedintermediate its ends, is supported by said cover adjacent to theforward end thereof.

6. A staple magazine unit and feed structure as set forth in claim 5 inwhich said pulley is positioned laterally of said track out of the pathof movement of said staples.

7. A staple magazine unit and feed structure as set forth in claim 5 inwhich portions of said pulley project into the path of movement of saidpusher for engagement therewith upon rearward movement of said coverfrom its closed towards its open position thereby to cause said pusherto be moved rearwardly by said rearward movement of said cover, and whensaid cover is moved from open to closed position, said pusher will beengaged and held by the rear end of a staple strip on said track andsaid spring will be extended to exert a forward feeding pressure on saidstrip.

8. A staple magazine unit and feed structure as set forth in claim 7 inwhich the front end of the lower run of said spring is secured to thelower rear end of said pusher and the projecting portions of said sheavepulley engage said pusher at points above that at which the end of saidspring is secured thereto whereby said projecting portions serve asfulcrums about which said spring exerts a downward pull, on the rear endof said pusher normally to hold it yieldingly in contacting engagementwith the upper face of said track.

9. A staple magazine unit and feed structure as set forth in claim 8 inwhich the upper face of said track is provided at its rear end withupwardly projecting stop means fOr engagement by said pusher to limitthe opening movement of said cover.

l0. A staple magazine unit and feed structure as set forth in claim 9 inwhich the rear end of said pusher may be manually raised against thedownward pull of said spring a sulicient distance to clear said stopmeans for entirely removing said cover and feeding means carried therebyfrom said magazine unit.

11. A staple magazine unit and feed structure as set forth in claim 4 inwhich means are provided for connecting the upper run of said spring tothe rear end of said track cover and the lower run of said spring to thelower rear end of said pusher whereby said spring serves to hold saidpusher in engagement with the upper face of said track and in contactwith said strip of staples to feed the latter forwardly of said track.

12. A staple magazine unit and feed structure as set forth in claim 4 inwhich a pair of said coiled tension pusher springs are each connected atone end With said cover adjacent the rear end thereof and a pair of saidpulleys are mounted on the inside of said cover, one at each side ofsaid track.

13. A staple magazine unit and feed structure as set forth in claim 5 inwhich said staple pusher and said coiled tension pusher spring thatcomprise said staple strip feeding means are mounted Within a housingdetachably connected at its rear end with the rear end of said trackcover with said sheave pulley rotatably mounted in the front end of saidhousing and with the said coiled tension pusher spring encased withinsaid housing having its front end connected to said pusher, its rear endconnected to said housing, and its intermediate portion trained aboutsaid sheave pulley.

14. A staple magazine unit and feed structure as set forth in claim 4 inwhich releasable lock means are provided between said track section andcov-er elements for holding said cover in closed position, said lockmeans including a spring member carried by one of said elements andyieldably engageable with xed structure on the other of said elements.

15. A staple magazine unit and feed structure according to claim 14wherein the said spring member is secured to and projects from the upperface of the track cover and said fixed structure is secured to saidtrack section, extending upwardly therefrom and over said spring member,for yielding engagement to urge said cover into snug engagement withsaid track section while locking said cover in closed position.

No references cited.

